This makes me think about something. When was it did the idea of slimegirls come to be? Much like banging them?

Necrobane said:

This makes me think about something. When was it did the idea of slimegirls come to be? Much like banging them?

I wouldn't be able to tell you when the first actual slimegirl as we know it came to be, but the trajectory that would eventually lead to the slimegirl probably began in 1986, when the first Dragon Quest game was published. The slime enemy introduced in that game was the first notable time a "slime/ooze" type enemy was depicted as cute, and since Dragon Quest went on to be a hugely influential on the RPG genre, cutesy slimes as basic enemies became a commonplace trope across video games as a whole. And since our culture strongly associates cuteness with femininity, once it became normalized to see slime monsters as "cute", the logical leap from "cute slime" to "cute slime girl" was bound to happen sooner rather than later.

XionGaTaosenai said:

I wouldn't be able to tell you when the first actual slimegirl as we know it came to be...

Amusingly, there's a Reddit thread on /r/AskHistorians of all places where some effort was made to figure out where the idea of slimegirls came from, one which even cites Danbooru at one point. The preliminary conclusions reached there is that "while there had been slime girls in some form since at least the 1960s, the 1980s and 90s would be when we would see the earliest developments for slime girls as we know them in fantasy, and it would be in the early 2000s when modern slime girls would emerge and be popularized, culminating in the 2010s monster girl boom prominently featuring them," though more research would need to be done. Personally, I'm more familiar with the pre-slime girl slime developments more, so that sort of research is out of my lane.